Kun, a little boy, enjoys a happy childhood until the arrival of his baby sister, Mirai. As the new baby becomes the center of his parents’ attention, he becomes increasingly jealous. Little by little, he withdraws into himself. In the backyard where he likes to take refuge, grows a magical family tree. Kun finds himself suddenly catapulted into a fantastical world where the past and the present mingle. One after another, he meets his relatives at different ages: his mother, as a little girl; his great-grandfather, as an energetic young man; and his little sister, as a teenager. Through these adventures, Kun is able to discover his own story. A wonderfully moving story about the invisible threads that connect generations and families, this was the first anime film to premiere at the Cannes Film Festival, making cinema history. Through visual mastery, and treading the narrative paths of the likes of Charles Dickens and Lewis Carroll, the director writes a love letter to the universal importance of family ties.